Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On both oral and intramuscular administration, the anabolic steroid stanozolol was found to increase protein C antigen concentrations in circulating blood. In fourteen healthy young volunteers (who received stanozolol orally, dose 10 mg/day) the average increase was 1.5-1.6 times the normal concentrations after 3-6 weeks' treatment and was accompanied by more moderate increases in the other vitamin K-dependent factors II, IX and X to 1.4, 1.4 and 1.2 times their normal concentration respectively. However, there was no change in factor VII. In sixteen elderly surgical patients, intramuscular injection (50 mg) one day prior to surgery induced a moderate increase within 24 hours (to 1.11 times the pretreatment concentration) and seven days after operation (to 1.19 times), and reduced the postoperative fall in protein C. Stanozolol administration seems to be a promising pharmacological method for increasing anticoagulant protein C levels in congenital and acquired deficiencies.
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PMID:Protein C, an anticoagulant protein, is increased in healthy volunteers and surgical patients after treatment with stanozolol. 654 15

Changes in protein C antigen (PC:Ag) have been compared with those in factor II, VII, IX and X antigens (II:Ag; VII:Ag; IX:Ag and X:Ag) in 10 patients starting on oral anticoagulant therapy with warfarin, monitored with thrombotest. Between days 0 and 3 of therapy, PC:Ag decreased at the same rate as VII:Ag, whilst IX:Ag, X:Ag and II:Ag decreased at progressively slower rates. On days 15 and 21, clotting proteins and PC:Ag did not differ significantly. Before and after warfarin, PC:Ag had the same mobility on crossed immunoelectrophoresis in Ca2+-free agarose gel; with Ca2+, a protein with faster anodal mobility appeared on day 1 and became maximal 5 d after warfarin was started. These findings indicate that the rate of PC decrease is closer to that of factor VII than those of factors IX, X and II, and that an abnormal PC with poor Ca2+-binding properties appears soon after treatment is started. The early decrease in the physiological inactivator (i.e. PC) might contribute to the poor antithrombotic efficacy of anticoagulant therapy during the first days.
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PMID:Decrease in protein C antigen and formation of an abnormal protein soon after starting oral anticoagulant therapy. 654 48

HeLa cells have undetectable tissue factor (thromboplastin) activity when measured by a one-stage coagulation assay. In contrast, these cells accelerated the factor VII-catalyzed cleavage of factor X. The two assays gave similar results after either heating the samples to 100 degrees C for 2 min or exposure to thrombin. Neither of these treatments altered the tissue factor activity of human foreskin fibroblasts, a cell type with high tissue factor activity. HeLa cells contain an inhibitor(s) directed against factor Xa but not thrombin. The inhibitor(s) was inactivated by exposure to thrombin or by heat treatment. Inhibition of factor Xa-catalyzed cleavage of a synthetic peptide was blocked by ethyleneglycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) so the inhibition was apparently dependent on divalent cations. Inhibition was not accelerated by heparin. The inhibitor(s) was not protein C or other serine proteases since it was not inactivated by diisopropylfluorophosphate. The factor Xa inhibitor(s) has been isolated from HeLa cells with an approximate 500-fold increase in specific activity. After SDS-polyacrylamide gel electrophoresis factor Xa-inhibitory activity was recovered from a region corresponding to the major Coomassie-staining band at 43 kDa and in lesser amounts from regions corresponding to 26 and 17 kDa. Cellular inhibitors of coagulation may partially explain the low apparent tissue factor observed in some in vitro cells and may serve a regulatory role in limiting the expression of tissue factor.
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PMID:Alterations in the apparent tissue factor (thromboplastin) expression in HeLa cells by a cellular factor Xa inhibitor. 663 60

Previous work has shown that two vitamin K-dependent plasma zymogens, factor X and protein C, each contain one residue of erythro-beta-hydroxyaspartic acid. In the present study, prothrombin, factor VII and factor IX were subjected to amino acid analyses for beta-hydroxyaspartic acid. Factor IX and factor VII each contain one residue of erythro-beta-hydroxyaspartic acid. Edman sequence analyses revealed that this residue occurs at position 64 in human and bovine factor IX. Inasmuch as the nucleotide sequence codes for aspartic acid at this position, it appears highly likely that beta-hydroxyaspartic acid is formed in these proteins by a post-translational hydroxylation of aspartic acid. In contrast, neither human nor bovine prothrombin contain beta-hydroxyaspartic acid.
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PMID:The occurrence of beta-hydroxyaspartic acid in the vitamin K-dependent blood coagulation zymogens. 668 26

Recent studies on the mechanism of initiation and regulation of blood coagulation are reviewed. In the intrinsic blood coagulation pathway, factor XII, prekallikrein (or factor XI) and high molecular weight kininogen from a complex on an anionic surface, such as exposed subendothelium at the site of vascular trauma. In complex, zymogen factor XII activates prekallikrein (or factor XI) by limited proteolysis to initiate the coagulation cascade. A similar initiating mechanism may be operative in the extrinsic pathway, where zymogen factor VII, complexed with a lipoprotein (tissue factor) and calcium ions, converts factor X to factor Xa. Factor Xa converts prothrombin to thrombin which converts soluble fibrinogen to an insoluble fibrin network which physically arrests the flow of blood from the damaged vasculature. In addition, thrombin converts protein C to activated protein C. Activated protein C functions as a negative regulator in the coagulation process by degrading factor VIIIa and factor Va.
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PMID:Enzymological aspects of blood coagulation. 668 3

Inhibition of activated human protein C was assessed in an amidolytic assay system using normal human plasma and samples from patients with hereditary coagulation abnormalities. In eight experiments normal plasma inhibited 63.5% (+/- 15.6%) protein C activity. Plasma from patients with haemophilia A or isolated factor V deficiency gave results which were not significantly different from normal. However, plasma from patients with combined factor V and factor VIII deficiencies inhibited an average of 24.5% (+/- 13.6%) of the amidolytic activity (P less than 0.01). Two of these plasma samples failed to inhibit any protein C activity. The relationship between the level of inhibitor and those of factor V and factor VII coagulant antigens (VCAg and VIIICAg) in the combined defect was investigated. There was no significant correlation between the level of inhibitor and any of the coagulation immunoassays on these stored samples but there was significant correlation between VCAg and VIIICAg in some assay systems. The levels of VCAg and VII CAg was low in most samples from patients with the combined defect which was in contrast to the results obtained when normal plasma was incubated with activated protein C in vitro. The findings are consistent with the presence of biochemical similarities between factors V and VIIIC molecules, but the role of activated protein C and its inhibitor in hereditary combined factor V/VIII deficiency remains to be firmly established.
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PMID:Quantitation of coagulant antigens and inhibition of activated protein C in combined factor V VIII deficiency. 681 16

We examined the changes in lipoprotein, apoprotein, and thrombophilia profile in postmenopausal women using a new cyclical sequential combined HRT regimen. The study medication consisted of two tablets of Hormonin (oestriol 0.27 mg, oestrone 1.4 mg and oestradiol 0.6 mg), daily and norethisterone (1 mg) BP (Shire Developments) for the last 12 days of every 28 day cycle. Serial fasting blood samples were collected at the beginning of the study and, thereafter, at 3-monthly intervals for 1 year, each patient acting as her own control. Thirty-five healthy postmenopausal women completed 1 year of follow-up and had a complete set of fasting blood samples. The lipid profile; total cholesterol, triglycerides, HDL, LDL, Apo AI, Apo AII, Apo B and Lp(a), as well as the coagulation parameters; antithrombin III, factor VII, fibrinogen, protein C and protein S, were measured at each occasion. There was a statistically significant drop in total cholesterol and LDL levels. Lp(a) level dropped after commencing treatment and remained below baseline for the rest of the study. The initial increase in Apo AII was not maintained for the duration of the treatment. The changes in Lp(a) and Apo AII were not statistically significant. The level of protein S dropped significantly throughout the study. The changes in other coagulation factors were not statistically significant. The effect of this hormonal combination on the lipid parameters is favourable, and although the change in protein S is striking, its clinical significance remains unclear.
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PMID:Effect of a new cyclical sequential postmenopausal HRT on lipoprotein, apoprotein and thrombophilia profile. 749 16

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.
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PMID:Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study. 751 43

We investigated the relationship between fasting insulin level and various hemostatic factors, including fibrinolytic factors (active plasminogen activator inhibitor-1 (PAI-1), tissue type plasminogen activator (tPA)-PAI-1 complex, plasmin-alpha 2-plasmin inhibitor (PIC), and D-dimer), coagulation factors (activated factor VII, factor VII coagulant activity and antigen, factor VIII, factor X, and fibrinogen), coagulation inhibitors (antithrombin III, heparin cofactor II, and protein C), and an acute phase marker (sialic acid) in 102 healthy individuals aged > or = 75 years (46 men and 56 women). Active PAI-1 levels had a significant negative correlation with PIC levels (r = -0.342, P = 0.0006), indicating that PAI-1 influences in vivo fibrinolytic activity in the very elderly. Gender differences were found in the relationship between insulin and hemostatic abnormalities, with the insulin level being positively correlated with coagulation factors in men (factor VIII activity: r = 0.422, P < 0.01; factor VII activity: r = 0.386, P < 0.01) and with hypofibrinolysis in women (active PAI-1: r = 0.549, P < 0.0001). Insulin levels were positively correlated with the levels of factor VII antigen and factor VII activity in men (P < 0.01), but there was no correlation with activated factor VII levels. The fasting insulin level was also correlated with the levels of heparin cofactor II and sialic acid in men (P < 0.05). However, other hemostatic factors were not related to the insulin level in either sex.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Gender differences of disturbed hemostasis related to fasting insulin level in healthy very elderly Japanese aged > or = 75 years. 757 76

The authors investigated the behaviour of some markers of the haemostatic balance in a group of patients with acute focal cerebral vasculopathy. The series consists of 70 female patients (mean age: 61 +/- 5), 25 of whom suffering from TIA and 45 from thrombotic stroke; 40 normal controls (mean age 43 +/- 5) were also considered. For each patient after an overnight fasting a withdrawal of venous blood was done within 24-36 hours after the admission. For each sample the determination of seven prothrombotic markers [(fibrinogen (F), factor VII (F VII), antithrombin III (AT III), protein C (PC), protein S (PS) (coagulometric method IL), tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1) (ELISA method Boehringer)] and of three prethrombotic markers [(fibrinopeptide A (FPA), beta-thromboglobulin (BTG) and D-dimer (D-D) (ELISA method, Boehringer)] was performed. The results obtained in the group of the cerebrovasculopathic patients compared to the controls showed a significant increase of F (p < 0.001), F VII (p < 0.005), BTG (p < 0.05) and D-D (p < 0.01), whereas significant differences regarding AT III, PC, PS, t-PA, PAI and FPA were not observed. The authors hypothesized that the increased levels of fibrinogen and factor VII in the cerebrovascular subjects, globally considered, may depend on a marked prothrombotic state, linked in a pathogenetic sense to the vascular disease; the existence of a prethrombotic state is also documented by the increase of betathromboglobulin and D-dimer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Haemostatic balance in patients with acute focal cerebral vasculopathy. 760 35


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